Pneumatic tire air pressure indicating means



March 25, 1941. J HUGGINS' JR 2,235,930

PNEUMATIC TIRE AIR PRESSURE INDICATING MEANS Filed Sept. 23, 1938 I 2 Sheets-Sheet l iNVENTOR WITNESS ATTORNEYS March 25, 1941. J s, JR 2,235,930

PNEUMATIC TIRE AIR PRESSURE INDICATING MEANS Filed Sept. 23, 1938 2 Sheets-Sheet 2 20% 34 a& a9

ATTORNEYS WITNESS Patented Mar. 25, 1941 PATENT orrlca PNEUMATIC TIRE AIR PRESSURE INDICATING MEANS James D. Huggins, Jr., Boiling Springs, N. C.

Application September 23, 1933, Serial No. 231,433

1 Claim.

My invention relates to improvements in air pressure indicating means adapted to be installed on an automobile or other vehicle having its wheels equipped with pneumatic tires.

One of the principal objects of my invention is to provide an air pressure indicating means so constructed and arranged, when installed on a vehicle equipped with pneumatic tires, as to indicate, through the medium of a set of dials, the

pressure of air in the individual tires, thus enabling the operator of the vehicle to easily determine whether said tires are properly inflated.

Another object of my invention is to provide air pressure indicating means of the character described connected to a common source oi elec tric energy, for instance the battery 01' the vehicle, for actuating the various dials in a manner whereby the pressure in the individual tires is indicated.

A further object of my invention is to provide a device of the character described which may be readily installed upon motor vehicles having front and rear wheels of the conventionalconstruction.

A still further object of my invention is to provide a device of the character described which is simple in construction, durable in use, eflicient in operation and economical in manufacture.

Other objects and advantages will be apparent from the following description, appended claim and annexed drawings.

Referring to the drawings wherein like reference characters designate like parts throughout the several views:

Figure l'ls a transverse sectional view of a rear wheel of a motor vehicle, partly in elevation, illustrating my invention as applied thereto.

Figure 2 is a view similar to Figure 1, illustrating my invention as applied to the front wheel of a motor vehicle.

Figure 3 is a rear elevation 01' the hub cap employed, illustrating my pressure actuated device attached thereto;

45 Figure 4 is a. detail longitudinal section view of the pressure actuated device.

a Figure 5 is a sectional view taken on the line 5-5 of Figure 4.

Figure 6 is a diagrammatic view of the elec- 50 trical circuit employed.

55 in Figure 1 and in the instance 01' a iront wheel the outer walls 0! said rims.

(Ci. fill-4%) rotatably mounted on the axle spindle "l for rotatlon relative thereto as clearly illustrated in ure 2.

The axle spindle 3 is fashioned with an axially extending bore 8 in which is mounted an electric wire 9 having a cover of insulatingmaterial and the rear end of said bore 8 communicates with an outwardly extending aperture ill through which the rear end of the wire 9 extends and is connected to a rotary contact ring ii insulated 19 from the axle spindle 8 by a body of insulating material 42 interposed therebetween as clearly illustrated in Figure l. The front end of the axle spindle i5 is fashioned with a socket having secure-d therein a contact member i3 insulated l5 rom said axle and connected to the outer end of the wire 9.

The outer end of the axle spindle l is likewise provided with a contact member M connected to the outer end or" a wire l5 extending there go through and connected to a terminal of one of a set oi dials l8 hereinafter more fully described. Adjacent the rotary contact ring ii, the stationary axle housing H surrounding the spindle S has mounted thereon and insulated therefrom, a spring pressed plunger I], one end of which has wiping engagement with the ring Ii and the opposite end connected to one end of a lead wire l8, the opposite end 03 said lead wire being connected to a terminal 0! another of said dials I8. 30

Each of the motor vehicle wheels is equipped with rims 19 connected to the hubs 5 by means of disks 2!! formed with recesses 2i adjacent said hubs and closed by hub caps 22. The rims is are provided with tire casings 23 equipped with 35 inner tubes 24 which have secured thereto connections 25 extending through apertures 26 in The outer ends of the air connections 25 have threaded thereon the upper ends oi flexible conduits 26', the lower ends of which are connected to pressure responsive and actuated devices 21, one 01 which is secured to the inner face of each of the hub caps 22 as clearly illustrated in Figure 3.

Inasmuch as each of the devices 21 are of a like construction, a detailed description of one will suffice. The device. 21 comprises an elongated cylinder 28 having open and closed ends 280. and 28b respectively. The open end 28a is threaded an appreciable distance within the bore 28c thereof. Threaded in said open end 2811 is a nipple. 29 having inner and outer reduced barrels ii and II respectively. The outer barrel" has clamped thereon the lower end of the conduit 20 and .the inner barrel ll has secured thereabout the outwardly extending end a rubber tube 32, the inner end of which is closed and normally engages a guide member or head 33 reciprocally mounted in the bore of the cylinder 28 and said guide head 33 is connected to aring 38 threaded in said bore adjacent the nipple 29 by means of a coil spring 35 surrounding said tube 32. g

Obviously, air introduced into the tube 32 through the conduit 20 connected to the inner tube 26 serves to expand the tube 32 and actuate the head 33 in a direction away from the open end of the cylinder. The tension of the spring 35 is sumcient to normally maintain the head 33 in a predetermined location in said cylinder relative to a predetermined amount of air pressure in the tube 32.

One section of the cylinder 28 adjacent the closed end, is fashioned with a longitudinally extending slot 35a through which extends an arm 36, the lower end of which is connected to the head 33 by means of an axially extending bolt 3? and adjusting nuts 31a. The upper end of the arm 36 has mounted thereon a yoke 38 provided with spaced fingers 3Q engaging the sides of an elongated resistance unit Mi overlying the slot 35a and said resistance unit is mounted on a pair of arms I carried on the cylinder 28, it being understood that said resistance unit is insulated from the arm ti and is provided with a binding post 62 connected to one end of an electric lead wire 43, the opposite end of which is connected to a finger 44 secured to a block of insulating material 55 mounted on the hub cap 22 and said finger resiliently engages the contact member B3 or i4 as the case may be.

Inoperation, each of the wheels of the motor vehicle are equipped with my invention in the foregoing described manner and the inner tubes of the tires of said wheels are inflated to a desired pressure. The indicators it are in the form of ammeters and are responsive to the adjustment of the fingers 39 relative to the resistance units 40 carried on the cylinders 28. Obviously, when one of the inner tubes becomes deflated or slightly deflated the tube 32 connected thereto by the conduit 26' will likewise become deflated and cause the head 33 to move towards the ring 34 by the action of the spring 35 thereby increasing the resistance in the unit 43 through the medium of the fingers 39 which are inner tubes in the various tires.

nected to the respective inner tube.

grounded to one side oi! the vehicle battery B through the medium of the hub cap, connected parts and the frame of the vehicle. When the resistance in the unit 40 is thus increased, the same will be indicated on the ammeters l6 connected in circuit therewith through the medium of the wiring heretofore described and thereby enabling an operator of the motor vehicle to determine the inflated condition of each" of the It is understood that a reverse movement of the head 33 will be had should the tires of one of them be overinflated through the medium of the tube 32 con- In order. to compensate for variations in the battery, adjustable resistance units 5d are interposed within the lead wires 65 and it respectively. The opposite terminal of the ammeters is are connected to one pole of an ignition switch 55 through lead wires 52 and said lead wires 52 have interposed therein fuses 53. The opposite pole of the ignition switch 58 is connected by a lead wire 58 to the positive side of the battery B and said wire 5% has interposed therein a main ammeter 55 oi an ordinary construction for denoting the condition 0! all of the circuits. The nuts 3'! may be adjusted by inserting a wrench or other tool through the slot a, although the cylinder 28 may be provided with another opening for this purpose. a

What I claim is:

In combination, an electric circuit having an electrically sensitive tire pressure indicating means interposed therein. a resistance in said circuit and including a wiper contact electrically engaging said resistance, and a tire pressure operated device interposed in said circuit for actuating said contact and comprising a cylinder provided with a bore, a member slidably mounted in said bore, a spring electrically connecting said member to said cylinder and for moving said member in one direction, an inflatable tube disposed wlthin said spring and connected to said cylinder and engaging said member for moving the latter in an opposite direction upon inflation of said member by pressure from said tire, and a circuit closing arm carried by said member and connected to said contact for shifting the latter relative to the resistance in response to pressure in the tire.

JAMES D. HUG-GINS, JR. 

